The issue was thrown into the public spotlight by the successive resignations of two prime ministers, Shinzo Abe and Yasuo Fukuda, the grandson and son respectively of former prime ministers.

Both lasted in office for only a year and their decisions to quit were criticized as a sign of the weakness of hereditary politicians.

"They have money, they have supporters and they have name value handed down from the parents," said Noriaki Tsuchiya, the deputy director of the Matsushita Institute of Government and Management.

"This is not good for Japan because [the] dynamism of political power is not [as] strong as other countries."

Ant v elephant

The Matsushita Institute was set up by the late founder of the electronics giant Panasonic to train promising young people hoping for a career in politics.

The aim is to develop a new breed of leaders, without family connections but with plenty of old fashioned Japanese virtues.

Students practice the martial art of Kendo - wooden sword fighting - and meditation, as well as holding debates and writing theses.

At dawn every morning they sweep the grounds, a taste of humble tasks on their way, they hope, to high office.

Back in Yokosuka, Shinjiro Koizumi is playing down his heritage - his grandfather and great-grandfather were parliamentarians too - telling supporters his father the former prime minister won't be joining him on the hustings.

"I get criticism every day for succeeding my father's seat," Shinjiro Koizumi told the BBC. "I want to overcome the criticism of hereditary politicians and fight against the strong headwind to win."

Katsuhito Yokokume, the lorry driver's son, is also hoping he will emerge victorious when the votes are counted.

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